Currently, with the rapid developments in the fourth generation mobile communication (4G) technology, development work for the fifth generation mobile communication (5G) standards is underway. According to the International Telecommunication Union (ITU), 5G technology is applicable to three typical application scenarios. The first application scenario is the enhanced mobile broadband (eMBB). In this scenario, the peak data rate of Internet access of an intelligent terminal can reach 10 Gbps or even 20 Gbps, which can support developments in bandwidth-consuming applications, such as virtual reality, live video broadcasting and sharing, cloud access anytime and anywhere, etc.. The second application scenario is the massive machine type communication (mMTC), which requires the 5G network to support connections with 1 million people and things per square kilometers. The third application scenario is the ultra-reliable and low-latency communication (uRLLC), which requires the 5G network to restrict the delay within millisecond to promote low-latency services such as intelligent manufacturing, remote mechanical control, assisted driving and automatic driving, or the like.
As stated above, in the mMTC application scenario, the number of connections with people and things supported by the 5G network may reach 1 million/square kilometers. With the massive terminals requiring network access, uplink traffic in the 5G network may increase greatly. Correspondingly, signaling overheads for uplink scheduling at 5G base stations may also increase drastically. Therefore, how to perform uplink data transmission in the 5G network becomes one of current research hotspots.